ProTaper手动锉预备弯曲根管的临床评价

目的评价ProTaper手动锉预备弯曲根管的临床疗效。方法将40颗具弯曲根管需行根管治疗的患牙随机分为两组：试验组用ProTaper手动锉及冠根向技术预备根管，对照组用K锉及逐步后退技术预备根管。两组均采用侧向加压充填法充填根管，用X线片评价根管预备的效果。结果ProTaper手动锉组无根管偏移、根尖堵塞、台阶形成、器械折断等并发症发生，能维持根管的弯曲度和走向，根管锥度和流畅度佳；操作时间短，且术后疼痛发生率低。结论ProTaper手动锉预备弯曲根管快速、安全、有效，临床应用价值较高。     

试件形状和光滑度对纵折牙牙本质黏接微拉伸强度的影响

目的评价试件形状和牙本质黏接面磨光对纵折牙牙本质黏接微拉伸强度的影响。方法选择新鲜拔除的人完整磨牙及前磨牙15颗,用慢速切割机先去除牙齿咬合面的釉质,再沿牙齿近远中向或颊舌向纵切牙体至釉牙骨质界下,作为纵折裂缝,随机分为3组。A组折裂面用Super-Bond C&B树脂水门汀黏接后,制成哑铃形试件;B组黏接后,制成棒状试件;C组的折裂面用800目碳化硅耐水砂纸湿磨光1min后,再黏接,制成棒状试件。分别测试三组的微拉伸强度。结果A、B、C 3组的微拉伸强度分别为(7．75±2．67)MPa、(21．19±4．90)MPa、(27．56±7．60)MPa。棒状试件组(B组)的微拉伸强度高于哑铃形试件组(A组)(P=-0．0000);磨光组(C组)的微拉伸强度高于非磨光组(B组)(P=0．0088)。结论试件形状和对牙本质黏接面磨光与否对纵折牙的牙本质黏接微拉伸强度有影响。     

Er、Cr:YSGG激光根管内照射对根管封闭效果的影响

目的:探讨常规根管预备后使用不同能量的Er、Cr:YSGG激光进行根管内照射对根充后根管封闭效果的影响。方法:选择新拔除的单根管牙105颗,分成7组,每组15颗牙。切除牙冠后,常规进行根管预备。第1组不进行任何处理,作为阳性对照组;第2组为1W、有水激光照射;第3组为1W、无水激光照射;第4组为2W、有水激光照射;第5组为2W、无水激光照射;第6组为3W、有水激光照射;第7组为3W、无水激光照射。根充后进行根尖微渗漏检测,评估根管封闭效果。采用单因素方差分析(Anova)进行多组间总体均数比较,q检验进行组间比较。结果:除3W无水组外,其他各激光组与对照组相比,根尖微渗漏深度均有显著性差异(P<0.05);其中1W无水组与对照组相比具有高度显著性差异(P<0.01)。结论:较低能量(除外3W、无水)Er、Cr:YSGG激光进行根管内照射,能够有效提高根管充填后的封闭效果,其中1W、无水激光照射时根管封闭效果最好。     

An in vitro comparison of canal preparation using two automated rotary nickel-titanium instrumentation techniques

AIM: The aim of this study was to compare the efficacy of root canal preparation using two automated rotary nickel-titanium instrumentation techniques with a double flared balanced forces hand preparation technique, using stainless steel files in extracted human teeth. METHODOLOGY: Sixty root canals in extracted human teeth were matched for curvature, length and diameter and divided evenly between three groups (group 1 = double flare using Flexofiles, group 2 = rotary nickel-titanium using McXIM instruments and group 3 = rotary nickel-titanium using Profile .04 Taper Series 29 instruments). The instruments were used according to the manufacturer's instructions in a torque controlled motor and handpiece (groups 2 and 3) and according to a predetermined procedure in group 1. A standardized radiographic technique using mercury as a contrast medium was used to evaluate the canal shape before and after preparation in the plane of maximum curvature. The pre- and postoperative radiographic images were compared against each other and with a predicted 'ideal preparation' calculated from a projection of the final instrument dimensions. The outcome measures were changes in canal dimensions as quantified by measuring the changes in the position of the inner and outer wall at 1 mm intervals. Alteration in canal curvature could be inferred by comparison with the ideal preparation. RESULTS: The degree of canal curvature did not influence the effectiveness of any of the techniques. The results showed no statistically significant differences in the outcome measures between the groups (two-way ANOVA). There were no significant differences in canal wall position changes at any level except the apical three, where significantly less change occurred in all groups (P = 1%). Instruments fractured in three canals, with acute curves in groups 2 and 3. CONCLUSIONS: Canal curvatures were equally and well maintained following preparation in all the groups, as long as the instrument did not fracture.     

Microleakage in conservative cavities varying the preparation method and surface treatment

Objective

To assess microleakage in conservative class V cavities prepared with aluminum-oxide air abrasion or turbine and restored with self-etching or etch-and-rinse adhesive systems.

Material and Methods

Forty premolars were randomly assigned to 4 groups (I and II: air abrasion; III and IV: turbine) and class V cavities were prepared on the buccal surfaces. Conditioning approaches were: groups I/III - 37% phosphoric acid; groups II/IV -self-priming etchant (Tyrian-SPe). Cavities were restored with One Step Plus/Filtek Z250. After finishing, specimens were thermocycled, immersed in 50% silver nitrate, and serially sectioned. Microleakage at the occlusal and cervical interfaces was measured in mm and calculated by a software. Data were subjected to ANOVA and Tukey’s test (α=0.05).

Results

Forty premolars were randomly assigned to 4 groups (I and II: air abrasion; III and IV: turbine) and class V cavities were prepared on the buccal surfaces. Conditioning approaches were: groups I/III - 37% phosphoric acid; groups II/IV -self-priming etchant (Tyrian-SPe). Cavities were restored with One Step Plus/Filtek Z250. After finishing, specimens were thermocycled, immersed in 50% silver nitrate, and serially sectioned. Microleakage at the occlusal and cervical interfaces was measured in mm and calculated by a software. Data were subjected to ANOVA and Tukey’s test (α=0.05).

Conclusion

Marginal seal of cavities prepared with aluminum-oxide air abrasion was different from that of conventionally prepared cavities, and the etch-and-rinse system promoted higher marginal seal at both enamel and dentin margins.     

氢氧化钙甘油糊剂对根管壁玷污层的溶解作用研究

目的观察氢氧化钙甘油糊剂对根管壁玷污层的溶解作用。方法30颗离体上前牙随机分为3组。常规预备根管后,A组封入氢氧化钙甘油糊剂,B组封入碘仿糊剂,C组封入樟脑酚。7d后清洗根管壁,并在扫描电镜下观察。结果A组根管壁玷污层明显较少,与B组和C组差异有统计学意义(P<0.01);B组与C组玷污层差异无统计学意义(P>0.05)。结论氢氧化钙甘油糊剂对根管壁玷污层有溶解作用。     

In vivo fractures of endodontically treated posterior teeth restored with amalgam

Abstract The cumulative survival rate (retention of both cusps) and the fracture pattern of 1639 endodontically treated posterior teeth were assessed in a retrospective study. All teeth had an MO/DO or an MOD cavity restored with amalgam without cuspal overlays. The 20-year survival rate of teeth with an MO/ DO cavity was markedly higher than that of teeth with an MOD cavity. The lowest survival rate was found for the upper premolars with an MOD cavity: 28% of these teeth fractured within 3 years after endodontic therapy, 57% were lost after 10 years, and 73% after 20 years. Generally, the cusp most prone to fracture was the lingual one, and lingual fractures caused significantly more damage to the periodontal tissues than did facial or total crown fractures. The severity of periodontal damage increased with posterior location of the tooth. By far the most serious failures, irrespective of the cavity type, were found for the upper second molar, as 10 of 29 fractures led to extraction. It is concluded that amalgam, especially in MOD cavities, is an unacceptable material for restoration of endodontically treated posterior teeth if used without cuspal overlays.     

镍钛旋转锉在老年人根管治疗中应用

目的:探讨机用镍钛器械ProTaper在老年患者根管治疗中应用的临床效果。方法:选取临床上因牙髓炎及根尖周炎需要进行根管治疗的老年患者46例,患牙56颗(94个根管),运用冠向下技术,采用机用镍钛器械ProTaper进行根管预备,热牙胶垂直加压技术充填根管。记录根管预备所需要的时间及器械折断的数量,根据治疗前、中及根充后的X线片评价预备及根充效果。结果:所有患者的根管预备锥度流畅度好,根管形态及工作长度无改变,无1例发生器械分离。结论:在老年患者的根管治疗中,使用机用镍钛器械ProTaper进行根管预备,可以获得比较好的临床效果。     

超声备根与手工备根的临床效果比较

目的 探讨超声波根管预备与手工根管预备在根管治疗中的临床应用效果。方法 将所选病例随机分成超声根管预备组和手工根管预备组,分别采用超声根管技术和逐步后退法技术进行一次性根管预备后封药,1周后观察效果。结果 超声备根组的自我症状改善,根管形态预备,叩痛及窦道消除等方面明显优于手工根管治疗组。结论 超声备根较手工备根可以提高治疗效果,缩短治疗时间。     

Shaping ability of two rotary instruments in simulated canals: stainless steel ENDOflash and nickel-titanium HERO Shaper

Aim To compare the shaping ability of two rotary instruments in simulated curved canals: stainless steel ENDOflash Files (KaVo, Biberach, Germany) and the recently introduced nickel‐titanium HERO Shaper instruments (Micro‐Mega, Besançon, France). Methodology Simulated root canals with 35° curves in resin blocks were prepared to size 30, .04 taper (HERO Shaper) using a crowndown technique or size 30, .02 taper (ENDOflash) using a rotary motion and a rotation speed of 400 or 250 rpm respectively. In both groups, irrigation was performed with 1 mL distilled water after each instrument size and Glyde (Dentsply Maillefer, Ballaigues, Switzerland) were used. Canals (n = 17 per group) were scanned before, during and after preparation. The assessment of preparation shape was carried out with a computer image analysis program. Material removal was measured at seven points beginning 1 mm from the end‐point of the canal. Statistical analysis was performed using Wilcoxon's test and Fisher's exact test (P < 0.05). Results No instrument fractures, apical blockage or loss of working length(WL) occurred. More zips (10 vs. 4) and more strippings (17 vs. 0) were created with ENDOflash compared with the HERO Shaper. There were significant differences in terms of the amount of resin removed on the inner wall of the curvature obtained with the two instruments (P < 0.0001). On average, HERO Shaper instruments removed material more evenly on the outer and inner wall of the curvature. Considering the different points of measurement, there were significant differences between the two systems both on the inner and outer walls at WL‐1, 2, 5 and 6 mm (P < 0.05). The HERO Shaper had a more centred enlargement compared with the ENDOflash. Conclusions Stainless steel rotary ENDOflash instruments did not perform as well as HERO Shaper instruments and created an increased risk of root canal transportation. Nickel‐titanium rotary HERO Shaper instruments maintained the original curvature significantly better.